The invention is concerned with the analysis of a remote sample by Raman spectroscopy, particularly for medical diagnostics. Raman scattering is extremely weak. In order to record laser-excited Raman spectra of delicate remote samples in a limited time one has to design a probe with maximum efficiency. The conversion of the laser radiation into Raman radiation should be as complete as possible and the probe has to collect the Raman radiation with a minimum of losses. At the same time heating of the sample by the absorbed laser radiation should be at a minimum in order not to denature the sample.
Such a probe allows the investigation of samples which cannot be brought into the spectrometer. Due to the low intensity of the Raman effect it is desirable to transmit a large radiant power of the laser radiation to the sample without endangering it and to collect the Raman radiation and transport it to the spectrometer as completely as possible. The contamination or pollution of the part of the probe which has been in contact with the (biological) sample should be removable by simple exchange, allowing cleaning as well as sterilizing. The exchangeable part of the probe should allow matching to different kinds of samples. The usual Raman spectrometers do not allow this.
Raman spectrometers with optical fiber bundles for the examination of remote samples are already on the market. Existing Raman spectrometers are for example connected to the sample by an optical fiber bundle without any coupling element or with a positive lens imaging Raman radiation from the sample into the optical fiber bundle.
It is the aim of the invention to provide a Raman spectrometer with an exchangeable probe that improves the figure of merit of existing Raman spectrometers.